This invention relates to apparatus and a method for ophthalmic irrigation, and more particularly, to an apparatus and method by which sterile, filtered irrigation fluid may be delivered to the eye by gravity feed at the high flow rates needed in ophthalmic surgery or in irrigation of the eye. Further, this invention relates to apparatus and a method by means of which sterile fluid may be administered sequentially to plural recipient sites. The recipient sites may, in fact, be successive patients.
In certain ophthalmic procedures, it is necessary to deliver fluid to the eye at high flow rates, typically on the order of 35 to 45 ml./min. For the purpose of comparison, these rates are about 20 times the flow rates used in the administration of fluids intraveneously
In present day practice, irrigation fluid, typically, so-called "balanced saline" solution, is supplied in prepackaged, sterile bottles of 500 ml., commonly referred to as "I.V." bottles. In use, such bottles may be hung from an I.V. stand, their stoppers pierced by a disposable unit providing a flow-controlling drip chamber, and the fluid conducted through a manifold to a handpiece by which the fluid may be directed to the site at which it is needed.
In certain ophthalmic surgical procedures, irrigation is conducted simultaneously with aspiration, through a unitary handpiece, and in such procedures, maintenance of an irrigation flow rate in excess of the aspiration rate is particularly critical. For such procedures, disposable irrigation/aspiration ("I/A") sets are typically used in association with an I.V. bottle and drip chamber. A typical I.V. set consists of an irrigation manifold (tubing and connector fittings), an aspiration manifold (tubing and fittings), and a drainage bag for aspirated fluid. Often, only a fraction of the contents of the I.V. bottle is used in a given procedure, but for reasons of sterility, the entire apparatus--bottle, drip chamber and I/A set--is discarded after each use.
One aspect of the present invention is a technique whereby a given bottle may, without compromising sterility, be used for up to any desired number of patients drawing sequentially from the same reservoir of fluid.
Another problem with irrigation/aspiration procedures has been the presence in the fluid of contaminants of a variety of types. For example, in recent years, despite the stringent quality control efforts of the suppliers of I.V. products, instances have been found of contamination by mold, fungus, and other contaminants, requiring recall of such products. Such occurrences demonstrate the need for routine filtration of ophthalmic irrigation fluids, but filtration has generally been thought to be inconsistent with the high flow rates needed for ophthalmic procedures.
It is, therefore, a principal object of the invention to provide, in association with a fluid reservoir such as an I.V. bottle, apparatus and a method for supplying sterile, filtered irrigation fluid to the eye. In another aspect of the invention, it provides apparatus and a method whereby irrigation may be drawn from a common reservoir and administered in a sterile manner to a succession of patients.